Adjusting Herbicide Adjusting Herbicide Programs to Emerging Programs to Emerging

Weed Problems Weed Problems in Peanutin Peanut

Eric P. ProstkoEric P. Prostko

Extension Weed SpecialistExtension Weed Specialist

University of GeorgiaUniversity of Georgia

Why do “new” weed problems occur?Why do “new” weed problems occur?

reliance on herbicidesreliance on herbicides decreases in cultivation decreases in cultivation ecological shiftsecological shifts herbicide resistanceherbicide resistance

New or Unique Weed Problems New or Unique Weed Problems in Peanuts in Peanuts

tropic crotontropic croton dayflower/spider-dayflower/spider-

wortwort ecliptaeclipta copperleafcopperleaf spiderflowerspiderflower redweedredweed ALS-resistant ALS-resistant

pigweedpigweed

Tropic Croton Tropic Croton (Croton glandulosus)(Croton glandulosus)

3rd most troublesome 3rd most troublesome weedweed

Cadre is weakCadre is weak not as competitive as not as competitive as

other weeds other weeds PRE - Valor or PRE - Valor or

StrongarmStrongarm POST - Ultra BlazerPOST - Ultra Blazer Cadre/Blazer Cadre/Blazer

tank/mixes???tank/mixes???

Dayflower/Spiderwort Dayflower/Spiderwort (Commelina spp.)(Commelina spp.)

Berrien, Brooks, Berrien, Brooks, Grady, ThomasGrady, Thomas

limited datalimited data Roundup is weakRoundup is weak PRE - Dual PRE - Dual

(timing)(timing) POST - BasagranPOST - Basagran others????others????

Asiatic

spreading

spiderwort

Tropical spiderwort, Cairo, GA, 2001

Residual Spiderwort Control in PeanutsResidual Spiderwort Control in Peanuts with Dual Magnum, Brooks County, GA with Dual Magnum, Brooks County, GA

2.2

7.6

0

2

4

6

8

Dual No Dual

Pla

nts/

ft2

Dual Magnum @ 1 pt/A Applied: July 2, 2001 Rated: August 1, 2001

b

a

Eclipta Eclipta (Eclipta prostrata)(Eclipta prostrata)

low, moist areaslow, moist areas limited biology datalimited biology data PRE - Strongarm, PRE - Strongarm,

Valor, Dual, OutlookValor, Dual, Outlook POST - Basagran, POST - Basagran,

Storm, Tough Storm, Tough timing is criticaltiming is critical

Eclipta Control in Peanuts with POST Eclipta Control in Peanuts with POST HerbicidesHerbicides

0

20

40

60

80

100

Cadre

Blazer

Storm

Basag

ran

Tough

2,4-

DB

Herbicide

Con

trol

(%

)

2" or less

3-5"

Grichar, 1997

Hophornbeam Copperleaf Hophornbeam Copperleaf (Acalypha (Acalypha ostryifolia)ostryifolia)

Randolph, TerrellRandolph, Terrell limited biology limited biology

datadata PRE - Valor or PRE - Valor or

StrongarmStrongarm POST - Ultra POST - Ultra

Blazer, StormBlazer, Storm

Hophornbeam Copperleaf ControlHophornbeam Copperleaf ControlRandolph County, GA - 2001Randolph County, GA - 2001

6 WAT

Untreated Strongarm Valor

Spiderflower Spiderflower (Cleome spp.)(Cleome spp.)

Laurens CountyLaurens County limited datalimited data PRE - PursuitPRE - Pursuit POST - Pursuit, POST - Pursuit,

Cadre, Ultra Cadre, Ultra Blazer (bloom Blazer (bloom stage)stage)

Redweed Redweed (Melochia corchorifolia)(Melochia corchorifolia)

low, moist areas low, moist areas hard seed coathard seed coat season long season long

germinationgermination PRE - Strongarm, PRE - Strongarm,

Valor, ZorialValor, Zorial POST - POST -

Basagran, Storm, Basagran, Storm, CadreCadre

ALS-Resistant Palmer PigweedALS-Resistant Palmer Pigweed

Burke CountyBurke County 20012001 do not use Cadre, do not use Cadre,

Pursuit, Classic, Pursuit, Classic, StrongarmStrongarm

Prowl, Sonalan, Prowl, Sonalan, Dual, Valor, Ultra Dual, Valor, Ultra Blazer, StormBlazer, Storm

SummarySummary

Newer soil applied herbicides will help Newer soil applied herbicides will help control some of the unique weed problems.control some of the unique weed problems.

Combinations of PRE and POST Combinations of PRE and POST treatments will provide consistent control.treatments will provide consistent control.

Need more information about biology and Need more information about biology and competitiveness of newer weed problems competitiveness of newer weed problems in order to make better control decisions.in order to make better control decisions.

University ofGeorgia

ExtensionWeed Science(gaweed.com)